Pump for refrigerating machines



Jan. 19, 19 32. 1', POTTER 1,841,499

PUMP FOR REFRIGERATING MACHINES Filed Nov. 4, 1929 2 Sheets-Sheet 1 flTT'URA/EW Jan. 19, 1932. 1, FQTTER 1,841,499

PUMP FOR. REFRIGERATING MACHINES Filed Nov. 4,1929 2 Sheets-Sheet 2 2Fry. 4

4 TTUR/VE/ Patented dart 19, 1932 THO I. rorrm, F PORT I PUMP FORREFRIGERATING MACHINES Application filed November 4, 1929. Serial No.40,5$$L

This invention relates generally to the art of mechanical refrigeration,and particularly to a refrigerating machine having a novel form ofcompressor and oil separating system.

The main object of this invention is to provide a refrigerating machineespecially adapted for small installations, which will be easy tomanufacture and which will require only the minimum amount of attentionin the way of service.

The second object is to provide a refri crating machine which will beexceedingTy quiet in operation and the use of which will not beaccompanied by the objectionable escape of refrigerants.

The third object is to provide a refrigerating machine having animproved form of compressor the parts of which are at all timescompletely lubricated) and made easily accessible, and also to includein said compressor a special form of oil separator by means of which thelubricant is removed from the refrigerant before same passes through thesystem.

The fourth object is to provide a special form of evaporator box whichwill provide automatic defrosting thereof.

These, and other objects, will become more apparent from thespecification following as illustrated in the accompanying drawings, inwhich:

Figure 1 is a plan-view of the machine showing the separator cut away ina horizontal section.

Figure 2 is an elevation of the machine showing its connections to arefrigerating compartment.

Figure 3 is an end elevation of the compressor showing parts broken awayin section.

Figure 4 is a vertical section through the compressor taken along theline 44 in Figure 2.

Figure 5 is a section through the compressor taken along the line 5-5 inFigure 2.

Figure 6 is a section taken along the line 6-6 in Figure 4.

Figure 7 is a section taken along the line 7-7 in Figure 4.

25 and thereby provide a perfect seal for Figure 8 is an enlar ed fraenta section through the packiii gland ry Similar numbers of re erencerefer to similar parts throughout the several views.

. Referring in detail to the drawings, there 55 is illustrated acompressor consisting of a base 10 on which is :mounted a cylinderhousing 11. which is secured to the base 10 by means of the bolts 12.The sides 13 of the cylinder housing 11 extend upwardly to form ee acrankcase preferebaly provided with the H fins 14 for the radiation ofheat. One side 15 of the crank case is closed and has formed thereinapair of bearings 16 and 17 preferably provided with bushings 18 inwhich jourea nals an eccentric shaft 19 on whose inner end is formed theeccentric 20 and on whose reduced end 21 is mounted a fly wheel beltpulley 22. The belt line of the pulley 22 is preferably as close aspossible to the outer to hearing to avoid over-hang. Around the looseend 21 is placed the gland bushing 23 provided with a shoulder .24adapted to engage a rubber gasket 25 in the recess 26 of a cap 27. Thereis a large clearance between the shaft portion 21 and the in+ terior ofthe bushing 23, and a corresponding clearance between the exterior ofthe bushing 23 and the recess 26. The end 28 of the bushing 23 isprovided with a seat which engages so the shouldered end 29 of the shaft19. v The clearances referred to make it possible for the bushing 23 tofloat upon the rubber gasket the compressor.

Within the cylinder housing 11 is formed a cylindrical bearing surface30 in which is mounted a cylinder body 31 having a bore 32 formed acrossthe diameter thereof entirely through same. Through the bottom of thehousing 11 are formed the curved inlet and outlet ports 33 and 34 whichcommunicate with the lateral passageways 35 and 36. The base 10' servesas a cover plate for the lower ends of the ports 33 and 34, and in someinstances the base 10 is made integral with the housing 11.

On the eccentric 20 is mounted an eccentric strap 37 which forms a partof the piston 38 mounted in-the bore 32. On each side of the cylinderbody 31 is formed a hub 39. On opposite sides of the cylinder body 31are disposed the projection 40 which forms a part of the side 15, andthe projection 41 which forms a part of the side 42 which reallyconstitutes a cover plate for the compressor and is removably securedthereon by means of the bolts 43. There is considerable clearance oneach side of the hubs 39 to prevent the cylinder body 31 from beingbound between the projections 40 and 41.

Mounted in the cover 42 is a ball 44 which is urged toward the eccentric20 by means of a spring 45 which reacts between the member 42 and a cup46 which is slidably mounted in the member 42. The ball 44 engages ahardened plug 47 in the end of the eccentric shaft 19. The function ofthe spring 45 is to hold the faces 28 and 29 to a seat at all times.

Forming a part of the cover plate 42 and at the top end thereof is anoil separator 48 in the bottom of which is mounted a gas equalizing pipe49 which communicates with the interior of the compressor and extendsalmost to the top of the oil separator 48. At one corner of theoil'separator and at the upper portion thereof is formed a bottomlesswalled compartment 50 from which warm compressed refrigerant can flowthrough the pipe 51 to a condensing coil 52 which may be cooled by thefan 53 on the shaft 54 of the motor 55 which is, in turn, mounted on anelevated base 56 which rises above the main base 57 on which is alsomounted the base 10 of the compressor. On the shaft 54 is also placed apulley 58 whose belt 59 drives the pulley 22. Obviously, heat may bedrawn from the coil 52 in any other convenient manner.

Underneath the elevated base 56 is placed a receiver 60 to whichliquefied cooled refrigerant passes from the coil 52 by means of thepipe 61. From the receiver 60 the refrigerant flows through the pipe 62to an expansion valve 63, which may be of any type suitable for thepurpose. From the expan' sion valve 63 the refrigerant is permitted toexpand into the expansion coils 64, which coils are wound on a castexpansion box 65 preferably provided with grooves for the reception ofthe tubing for the purpose of providing a better contact between thetubing and the metal inthe box, and also to prevent frost from formingan insulation which will retard the flow of heat from the interior ofthe box to the interior of the coil 64.

The relation of the mass of metal in the box 65 and the refrigeratingcapacity of the machine, and also to the loss of heat by leakage in therefrigerating compartment itself, is such as to provide automaticdefrosting of the expansion coils 64 during the interval in whichheat-pumping is stopped by means of the thermostat 66 mounted atapproximately the middle of the height of the refrigerating compartment67, which thermostat controls the operation of the motor 55. Saiddefrost ing takes place before the ice cubes which have been formed inthe trays 68 begin to melt. In other words, there is a definite lag orretarding of the flow of heat between the food 69 and the ice in thetrays 68. If there is a deficiency in this lag, automatic defrostingwill occur, but the ice will melt each time the motor 55 is shut down,due to a minimum temperature of the compartment 67, and if the lag istoo greatthat is if too much metal or heat-storing material isinterposed between the food 69 and the icethen defrosting will not occurunless the door of the compartment 67 is open.

From the expansion coil 64 the warm gaseous refrigerant returns by wayof the pipe 70 to the intake port 33 of the compressor where it iscompressed through the operation of the piston 38, which alternatelycovers and uncovers the ports 33 and 34 and discharged through the port34, and through the pipe 71 enters the upper portion of the oilseparator 48. Between the bottom of the oil separator 48 and thelowermost point of the compressor casing is formed a connecting passage72 by means of which oil can flow to the bottom of the compressorwithout any liability of its becoming broken up intospray and possiblycarried over to the condenser.

In the above described apparatus the separation of lubricant andrefrigerant is complete.

It will be noted in Figure 7 that the intake and exhaust ports 33 and 34are curved, the curvature of the inner side of each port conforming tothe exterior of the piston. The purpose of this formation is to secure arelatively qulck opening and closing of the ports without anyobjectionable retarding of such opening and closing as would beoccasioned if the piston was round and the port face was straight. Itcan also be seen that by this arrangement the working parts of thecylinder are at all times perfectly lubricated and the cylinder body 31is held to its seat at all times by the pressure within the crank caseadded to the weight of the body 31.

Between the bearings 16 and 17 is formed an elevated oil reservoir 73which is kept full by splash from the moving parts.

, It will be noted in Figure 6 wherein the eccentric is on a dead centerthat the outlet port 34 is somewhat nearer the bore 32 than is the inletport 33, for: the simple reason that during the operation of thecompressor a certain amount of lap is necessary and if this should existon the exhaust side then the compressor would be apt to pound, due tothe trapping of liquids on the compression stroke; whereas a.considerable lap on the intake side would not be objectionable since itwould merely result in a creation of a partial vacuum for a short spaceof time.

separator in which freed refrigerant can be collected and Withdrawn forcondensation purposes.

2. A compressor for refrigerating ma-i chines consisting of a cylinderhousing, a crank case extending above thetop of said housing, and alsoincluding one side of said crank case, a pair of bearings supported bysaid crank case side, an eccentric shaft journaling in said bearings,the inner end of said eccentric shaft having an eccentric thereon, anoscillating cylinder body mounted in said cylinder housing having a boreextending diametrically therethrough, said cylinder housing having apairof ports formed therein adapted to engage opposite sides of saidcylinder body bore at its extremes of oscillation, a piston in saidcylinder body having a strap at its upper end encircling said eccentric,a cover plate for said crank case, an end thrust stufiing box on theouter end of said eccentric shaft, and a spring between said eccentricand said cover plate for maintaining a seal in said stuffing box.

3. In a compressor, the combination of a somewhat oval crank case havingits smaller end lowermost and containing a. journal for an oscillatingcylinder body, a closure for one side of said crank case forming a partthereof, an eccentric shaft mounted in said closure having an oil wellformed around the middle portion thereof, an eccentric on the inner endof said shaft, an oscillating cylinder body and piston operated by saideccentric, said eccentric shaft having a shouldered outer end, a packinggland encircling said reduced end and spaced therefrom but contacting atone end with said shaft shoulder, a resilient packing between said glandand its surrounding closure structure, said gland floating between saidresilient gland and said reduced shaft portion, and a spring for urgingsaid eccentric shaft shoulder to seat with said gland.

4. In a compressor, the combination of a crank case, a compressioncylinder at the lower end thereof and an operating eccentric in theupper portion thereof, an oil separator mounted above the top of'saidcrank case, an oil return duct communicating between the bottom of saidseparator and the bottom of said crank case, a pressure balancing ductcommunicating between the top of said crank case and the top of saidseparator, and a bottomless compartment within said separator whoselowermost portion lies between said oil outlet and the top of saidbalancing duct, from which compartment the compressed refrigerant freedfrom lubricant can be drawn.

5. A compressor consisting of an oscillating pumping element having itscylinder lowermost and having its operating shaft uppermost and itscylinder bore extending entirely through its cylinder body, a journalfor said cylinder body having curved ports formed therein providing anexcess of lap on the intake side, an elevated oil separating compartmentincorporated in said pumping element wherein compressed refrigerant maybe delivered and wherein any oil which has been carried over from saidcompressor may be precipitated and wherein said precipitated oil may bereturned to the bottom of the compressor, the bottom of said compressorconstituting an oil reservoir, a pressure equalizing pipe communicatingbetween the upper portion of said oil separating compartment and theupper portion of said compressor, and a collector for refrigerant whichhas been freed from lubricant having its intake between the top of saidequalizing pipe and the bottom of said oil separating com partment.

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